This invention relates to the conversion of olefins according to the olefin reaction, to catalysts therefore and to a method for modifying the activity of such catalysts. In accordance with one aspect, this invention relates to a catalyst comprising tungsten, silica and at least one titaniferous agent or component suitable for use in the disproportionation and isomerization of olefins.
In accordance with another aspect, this invention relates to a catalyst suitable for use in the disproportionation and isomerization of olefins comprising silica and tungsten promoted with at least one titaniferous agent or component.
In accordance with another aspect, this invention relates to a process for the disproportionation and isomerization of olefinic hydrocarbons with a disproportionation catalyst modified as hereinbefore described under conditions of temperature and pressure which effect disproportionation and isomerization of olefinic hydrocarbon feeds.
The disproportionation or metathesis of olefins is a reaction in which one or more olefinic compounds are transformed into other olefins of different molecular weights. The disproportionation of an olefin with itself to produce an olefin of a higher molecular weight and an olefin of a lower molecular weight can also be referred to as a self-disproportionation. For example, propylene can be disproportionated to ethylene, and cis-, and trans-2-butene.
Another type of disproportionation involves the cross-disproportionation of two different olefins to form still other olefins. An example would be the reaction of one molecule of 2-butene with one molecule of 3-hexene to produce two molecules of 2-pentene.
By the term "disproportionation" or "metathesis" throughout the specification is meant the conversion of the feed olefinic (or unsaturated) hydrocarbon to a mixture of olefinic (or unsaturated) hydrocarbons having different numbers of carbon atoms than the feed hydrocarbons.
Among the catalysts that have been developed for disproportionation are those comprising silica containing a catalytic amount of tungsten oxide. The present invention is based upon the discovery of a way to improve the activity of such a catalyst for the isomerization of olefins.
Previously it has been found that the activity of olefin reaction catalysts, e.g. disproportionation or metathesis catalysts, can be modified by admixture with a double bond isomerization catalyst. For example, mixtures of olefin reaction catalysts with magnesium oxide or zinc oxide are particularly effective in increasing conversion and/or widening the spread of products.
It has now been found that the isomerization activity of an olefin reaction catalyst, i.e. a disproportionation or metathesis catalyst, can be modified by treating the catalyst with a titaniferous agent.
Accordingly, an object of this invention is to provide a method for the conversion of olefins.
Another object of this invention is to provide a catalyst for the conversion of olefins.
Still another object of this invention is to provide a method for converting olefins to olefins having different numbers of carbon atoms from the feed hydrocarbons.
Still another object of this invention is to provide a method for modifying the activity of a disproportionation catalyst for the isomerization of olefins.
Other aspects, objects, and the several advantages of the invention will be apparent to one skilled in the art upon reading the disclosure including a detailed description of the invention and the appended claims.